The Search for Proton Decay at Super-Kamiokande

Seventy years ago (in 1929) Weyl proposed that the proton was absolutely stable. In later years this hypothesis was advanced by others including Stueckelberg and Wigner. Nonetheless, experimental searches for baryon number violation have been conducted since 1959. These studies are motivated by a variety of concerns including the lack of observation of a baryon number dependent force as required by a new local symmetry such as baryon conservation. Another motivation is the emergence of baryon and lepton number violating processes in grand unified and supersymmetric theories. This is a consequence of baryons and leptons being placed in the same multiplets. Baryon number violation can occur in over fifty modes of nucleon decay to elementary particles as well as in neutron-antineutron oscillations. Each of these processes can be studied by Super-Kamiokande through a separate customized analysis. In this talk we present results on two proton decay modes, p 6eπ and p 6νK ,for a 33 kton exposure at Super-Kamiokande. Both of these modes are of interest in the minimal supersymmetric (SUSY) SU(5) theory. Here p 6 νK is the dominant mode with a partial lifetime that varies from 10 to 10 years. For p 6 eπ the partial lifetime in SUSY SU(5) is 5 x 10 years or longer.